| Welcome to Smallbore Rifle Silhouette by Jerry Webster | |||
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Here is a ballistics chart for a 22 caliber bullet weighing 40 grains with a muzzle velocity of 1080 feet per second. This is typical for target ammunition. This accurately represents what I am using in the Smallbore Rifle Silhouette competition. It is not intended to be a perfect view of the bullets path. The actual velocity of any ammunition varies from what is stated on the box to how it shoots in any given firearm. The elevation, barometric pressure and the height of your sight above the rifle can all change the actual results. The velocity of the same ammunition in a different firearm can vary. This is intended to be a guide to help anyone new to the sport. It gives a person an idea of the adjustments that are necessary to be made in a match by showing the mechanics of the bullet's flight.
PATH = Distance from the bullet
path in
inches.
ANGLE = The amount of drop in Minutes of angle (scopes typically adjust 1/4minute or 1/8 minute per click)
VELOCITY = The speed of the bullet after it has travelled to
the target specified.
| Chicken | Pig | Turkey | Ram | |
| RANGE | 40 Meters | 60 Meters | 77 Meters | 100 Meters |
| VELOCITY | 968 fps | 917 fps | 877 fps | 822 fps |
| PATH | 0 | -1.3 inches | -3.7 inches | -9.5 inches |
| PATH | +0.9 | 0 | -2.0 inches | -7.3 inches |
| PATH | +2.0 inches | +1.6 inches | 0 | -4.6 inches |
| PATH | +3.8 inches | +4.4 inches | +3.5 inches | 0 |
| Chicken | Pig | Turkey | Ram | |
| RANGE | 40 Meters | 60 Meters | 77 Meters | 100 Meters |
| VELOCITY | 968 fps | 917 fps | 877 fps | 822 fps |
| ANGLE | 0 | -1.9 min | -4.3 min | -8.3 min |
| ANGLE | +1.9 min | 0 | -2.3 min | -6.3 min |
| ANGLE | +4.3 min | +2.3 min | 0 | -4.0 min |
| ANGLE | +8.3 min | +6.3 min | +4.0 min | 0 |
You need to be able to trust your scope adjustments on-the-fly during a match. There are no sighting shots allowed after a match has started. I am not saying that you need an expensive scope. I started using a Bushnell 6x-18x-50mm that I spent about $110 for and I was very happy with its performance. When sighting in for a match, competitors document the settings they need for each animal. I have a paper I keep on the clipboard we have for the score sheet that shows my settings for each rifle. It is also easier to do when you have a target style scope. There is a scale on the turret for the adjustments.
When I had to improvise with a hunting type scope adjustment scale, I drew 4 copies of the scale on a small piece of paper; one for each animal setting. I made copies of this for each shoot. Then I could mark my settings for each animal on the paper to have during the match.
Here is an example of the adjustments I typically make in a match with my rifle. This again is just a guide. Exactly how much adjustment is needed will vary with any ammunition, rifle and scope combination. This also demonstrates the need for a reliable scope. If it does not adjust consistently, you will be missing targets. It is too easy to miss targets when your scope is adjusted properly to be missing them because it is not sighted in correctly.
The way the adjustment averages shooting my Anschutz with a Weaver T36 Scope with 1/8 minute adjustment accuracy is as follows:
With the rifle sighted and zero'ed at the Chickens (40m) it is an upward adjustment of 1-1/4 minutes to be sighted for the Pigs (60m).
From the Pigs, up another 1-5/8 minutes (2-7/8 minutes total from the Chickens) to be sighted for the Turkeys (77m).
Then up another 4.0 minutes from the Turkeys (6-7/8 minutes total from the Chickens) to be sighted for the Rams (100m).
© Copyright 2009